On Mon, Sep 14, 2015 at 10:23 PM, Marc Zyngier [off-list ref] wrote:

On 14/09/15 16:06, Y Vo wrote:

quoted

On Mon, Sep 14, 2015 at 9:47 PM, Arnd Bergmann [off-list ref] wrote:

quoted

On Monday 14 September 2015 16:39:43 Y Vo wrote:

quoted

On Mon, Sep 14, 2015 at 4:11 PM, Arnd Bergmann [off-list ref] wrote:

quoted

On Saturday 12 September 2015 12:55:55 Y Vo wrote:

quoted

On Fri, Sep 11, 2015 at 11:45 PM, Arnd Bergmann [off-list ref] wrote:

quoted

On Friday 11 September 2015 22:06:58 Y Vo wrote:

Example for configure GPIO_DS13 as interrupt and use as button with
the current gpio driver:
        gpio-keys {
                compatible = "gpio-keys";
                button at 1 {
                        label = "POWER";
                        linux,code = <116>;
                        linux,input-type = <0x1>;
                        interrupts = <0x0 0x2d 0x1>;
                };
        };

Wait, this looks wrong: the gpio driver doesn't actually see
the connection here and won't be able to configure the interrupt
correctly. The interrupt is already owned by the gpio driver, so
you cannot use it in the button node.

In summary:
- Our GPIO doesn't support interrupt controller.
- There are 6 pins which used the external interrupt from GIC, so all
setup for those irqs are from gic driver. The GPIO driver only
configure to wire those lines.

For your concern:
- That's correct: if we use that defined, the gpio driver never saw
the connection here (That's why it already is configued at the
beginning).
- At the first time, we tried to use the define: <&sbgpio 13 1>, it
means using the GPIO_DS13, it will go into the GPIO driver to setup,
but there is another problem which I have sent out to all of you:
+ It will go into gpio_keys_setup_key (gpio_keys.c driver) function,
then set the irqflags = IRQF_TRIGGER_RISING | IRQF_TRIGGER_FALLING,
but the gic only support IRQ_TYPE_LEVEL_HIGH && IRQF_TRIGGER_RISING,
so it always returns failed at gpio_keys_setup_key function. Please
see the gic_set_type at gic driver.

Hmm, I see now how the event handling in the gpio-keys driver differs
between irq mode and gpio mode, where gpio mode relies on getting
a separate event for the release. This is certainly something that
could be changed in the gpio-keys driver as an extension, but that
seems to be what Laxman Dewangan did when he introduced the irq-mode.

quoted

static int gic_set_type(struct irq_data *d, unsigned int type)
{
        void __iomem *base = gic_dist_base(d);
        unsigned int gicirq = gic_irq(d);

        /* Interrupt configuration for SGIs can't be changed */
        if (gicirq < 16)
                return -EINVAL;

        /* SPIs have restrictions on the supported types */
        if (gicirq >= 32 && type != IRQ_TYPE_LEVEL_HIGH &&
                            type != IRQ_TYPE_EDGE_RISING)
                return -EINVAL;

        return gic_configure_irq(gicirq, type, base, NULL);
}
+ Another issue: in order gpio_key works it needs the status of GPIO.
For our chip, when the GPIO is configued as interrupt, we need to
access to GIC register to read the real status, it is not acceptable
to implement accessing GIC registers at gpio driver. The function
irq_get_irqchip_state(..) also doesn't work in our chip too. Because
it needs to access different offset.

I thought we had solved that problem long ago when you first
submitted the driver.

Did 1b7047edfcfb25 ("genirq: Allow the irqchip state of an IRQ to be
save/restored") not address the problem for you? You were on
Cc to that patch and should have spoken up when the code that was
merged was not sufficient.

Yes, I am in this mail-list too, but I also had a issue on this, I
think you are still in my submitted for this.
Currently, irq_get|set_irqchip_state(..) supports access to
GIC_DIST_ENABLE_SET, GIC_DIST_ACTIVE_SET, GIC_DIST_PENDING_SET. But
our hw only has the valid value at SPISR register ("[PATCH v4 2/3]
irqchip: GIC: Add support for irq_{get,set}_irqchip_state"), so I
still can not use it.

And I asked Feng Kan to explain *why* it doesn't work, but nobody ever
bothered giving me a straight answer on that:

https://www.mail-archive.com/linux-kernel at vger.kernel.org/msg892972.html

The GIC400 TRM explicitly states that reading GICD_SPISRn is the same as
reading GICD_ICPENDRn. if that doesn't work for you please explain why.

If I can get a reasonable explanation on *why* it doesn't work, then we
can look at having an X-Gene specific workaround.

I am checking and let you know soon.

Thanks

Thanks,

        M.
--
Jazz is not dead. It just smells funny...